736 JOURNAL OF FORESTRY 



by 10 inches; 35 feet by i foot; 40 feet by 1.5 feet, the diameters being 

 measured at base. 



There are a good many hemlocks 6 m. (20 feet) high, and there are 

 numerous individuals of all sizes down to 15 cm. (6 inches) in height. 

 They nearly all have the stunted appearance common to bog trees in 

 this region. Many of them are dead in some portion, particularly at 

 the top. The trunks of the larger specimens show the distinctly conical 

 form commonly seen in bog trees — that is, they have grown in thick- 

 ness near the base disproportionately to their growth in height. 



Willows and alders are abundant in the marginal ditch, but they stop 

 short at the edge of the sphagnum. Hard-hack is abundant in the mar- 

 ginal ditch and in the large swamp which borders the bog on the north. 

 Douglas fir is more abundant in this bog than in any other examined. 

 The largest specimens are 2 meters (6.5 feet) high. Seedlings are not 

 very abundant. Seedlings of giant cedar are abundant and some trees 

 reach a height of 5 m. (16.5 feet). 



2. ALASKA BOGS 



In the Alaska bogs visited, the advance of the forest is less con- 

 spicuous than in the Puget Sound bogs. In many cases the trees are 

 prostrate in the bog, although the same species grows erect alongside 

 it. In some cases (Three Saints Bay and Sand Point) the bogs are in 

 treeless regions, so that the question there is really the advance of 

 alpine shrubs rather than of trees. The presence of broadleaf species 

 in bogs is also much more common in Alaska than in the Puget Sound 

 region. Species of birch and of willow are common. Both are real 

 invaders, though often much stunted and frequently prostrate. 



The conifers have invaded the small patches of bog found in the 

 tundra at Dixon Harbor (long. 136° 57' W., lat. 58° 22' N.). The 

 three species of conifers found in both bog and forest are lodgepole 

 pine, Alaska cedar (Chamcecyparis nootkatensis Spach.), and the 

 Sitka spruce. The only conifer found in the forest, but not in the bogs 

 at this point, was the Alpine hemlock (Tsuga mertensiana Sarg.). This 

 species, along with the others, had found a foothold in the thin layer of 

 living mosses and decaying organic matter overlying the rocks and con- 

 stituting the substratum of the tundra, but had not yet progressed into 

 the sphagnum. 



The peat-bog birch is found in these bogs. It tends to become erect 

 in them and sometimes reaches a height of 30 cm. (i foot), while it is 

 prostrate in the crevices of the near-by rocks. It was not found in the 



